This invention concerns a paper feeding apparatus in reproducing machines or likes for feeding paper sheets one by one from the uppermost surface of a bundle of stacked paper sheets.
Conventional paper feeding apparatus for feeding paper sheets one by one from the uppermost surface of a bundle of stacked paper sheets are adapted to feed sheets by the rotational force of feed rollers in contact with the uppermost surface of a bundle of stacked paper sheets.
Such a structure has, however, a disadvantage of frequently resulting in a sheet multi-feed in which two or more paper sheets, that is, not only the uppermost paper sheet but also the succeeding paper sheet (or sheets) feed simultaneously.
In view of the foregoing, means for preventing the above multi-feed have been devised including, for example, sheet feeders wherein the frictional force at the contact portion between the feed rollers and the uppermost paper sheet are changed by varying the materials of the feed rollers, contact loads exerted by the feed rollers and the like.
It is, however, difficult to positively prevent the multi-feed by the means above described.
The above difficulty is attributable to the fact that the multi-feed is mainly caused by the frictional engagement between paper sheets and the absence of air therebetween, and mere increase in the frictional force between the uppermost paper sheet and the feed rollers as described above have no substantial effects for the separation at all unless the vacuum between the uppermost paper sheet and the succeeding paper sheet is broken to reduce the attraction force therebetween.
This invention has been made in view of the foregoing and the object of the invention is to provide a paper sheet feeding apparatus comprising means for moving feed rollers transverse to the paper feed direction so that the uppermost paper sheet can be displaced relative to the next paper sheet in a direction crosswise to the paper feeding direction to form a gap between the uppermost paper sheet and the next paper sheet thereby releasing the vacuum attraction therebetween for improved feeding reliability.